(1) Field of the Invention
The instant invention is directed to the field of signal processing, and more particularly, to an adaptive statistical filter providing improved performance for target motion analysis noise discrimination.
(2) Description of the Prior Art
Target motion analysis processors are employed wherever it is desirable to determine the range, velocity and bearing of a remote target. The typical target motion analysis processing system includes some sort of a data sensor, such as a sonar or radar, an adaptive filter coupled to the data sensor and a target motion analysis processing module coupled to the adaptive filter.
The sensor is responsive to the radiation emitted by or reflected off the target to provide a data stream representative thereof. The character of the data stream, in any given case, has different "static" and "dynamic" characteristics that depend upon the relative velocities of, and relative positions defined between, the data sensor and the remote target, as well as upon the state of the noise in the communication channel therebetween, among other factors.
The adaptive filter adaptively filters the data stream to extract the "static" and "dynamic" characteristics of the data stream from noise, and the target motion analysis processing module is responsive to the extracted characteristics of the data stream to provide estimates of the bearing, range and velocity of the remote target.
However, the heretofore known adaptive filters were fixed-order filters, so that, depending on the particular order of the fixed-order adaptive filter, it often happened that the noise represented by the "static" and "dynamic" characteristics of the data stream provided by the data sensor was on the order of at least one of the predetermined number of parameters being estimated by the fixed-order adaptive filters. Being thus disabled from distinguishing noise from target information, the heretofore known target motion analysis processing systems having fixed-order adaptive filters were thus subjected to non-optimum performance to a degree that depended on the degree to which the noise characteristics of the measurement data stream were on the order of one or more of the predetermined number of parameters estimated by the fixed-order adaptive filters.